Upgrading Drupal

Updating from 7.24 to 7.25, and also doing a module update after the Drupal version update, I rec'd two errors each time. Looks to me like perhaps the updates to the database for the core and the module may have proceeded properly and only the reporting of the "success" page was hindered by the error? I would like confirmation that, despite these errors, the basic functioning of the site was updated and all is as it should be.

Notice: Undefined index: update_success in update_results_page() (line 177 of /home/northwes/public_html/update.php)

and

We have been told by a couple of Drupal developers that once Drupal 8 is live, versions of Drupal 6x will not longer be supported? We are most concerned about security udpates and platform stability and understand the clients would not have access to new features. But we cannot recommend to our clients to stay in Drupal (only a few non-profits we support who cannot afford to upgrade apply) if there is a high danger if security breaches and instability.
Can someone please clarify this for us?

Hello Everyone,

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Hi,
I installed version 7.22 of Drupal. Whene I want to display webforms sumbittion by user I got this message error in red :
There is a security update available for your version of Drupal. To ensure the security of your server, you should update immediately! See the available updates page for more information and to install your missing updates.

Hi to everybody.
Drupal is stressing me everyday on update it to the lastest versione. I've done it today, but drush is working strange.

I performed drush up drupal, but it updates to 7.23, instead of the latest version. This is what I get:

Security update required!error
Drupal core 7.23
Recommended version: 7.23 (2013-Aug-08)
Download
Release notes
Security update: 7.24 (2013-Nov-20)
Download
Release notes
Latest version: 7.25 (2014-Jan-03)
Download

How can I force drush to update to 7.24?